Water vapor replenisher for gaseous discharge switching devices



May 7, 1957 HE| 2,791,715

WATER VAPOR REPLENIsHx-:R GASEOUS DISCHARGE SWITCHING DEVICES 5 Sheets-Sheet 1 Filed Sept. 6. 1952 May 7, 1957 H. HEINS 2,791,715

WATER VAPOR REPLENISHER FoR GAsEoUs DISCHARGE SWITCHING DEVICES 3 Sheets-Sheet 2 Filed Sept. 6, 1952 FIG. 2

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INVENTOR. M Mw May 7, H HEINS WATER VAPOR REPLENI'SHER FOR GASEOUS DISCHARGE SWITCHING DEVICES Filed Sept. 6, 1952 5 Sheets-Sheet 3 l f Y, t

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INVENTOR.

nited States; Patent i WATER VAPOR REPLENISHER FOR GAsno-'Us DISCHARGE svmcnmc DEVICES Application September 6, 1952, Serial No. 308,211 2 claims. (c1. 313-4180) This invention relates to gaseous discharge switching devices and more particularly to means for replenishing a component of the gaseous medium employed in such devices.

Gaseous discharge switching devices are commonly employed in radio direction and range systems to permit the use of `a single antenna and are referred to in the art as transmit-receive devices. Generally, such devices contain a gaseous medium under reduced pressure with a predetermined percentage of water vapor as a component thereof.

Water vapor is employed as a component of the gaseous medium as an electron capture agent. After cessation of a radio frequency discharge, free electrons remaining in the vicinity ofthe discharge gap cause a loss in intensity of the returned low level signal. It is therefore, necessary that these electrons be removed from the gap. Water vapor is an effective electron capture agent and causes the formation of negative Water vapor ions. The relatively heavy negative water vapor ions, because of their low mobility, do not extract appreciable energy from the returning low level signal.

It has been observed experimentally in the art that after a certain period of operation the gas content is altered, principally by clean-up of the water vapor. At high power transmission levels the rate of clean-up of the water vapor appears to be a function of the power level. In -many applications of radio direction and range sys- 'tems the rate of removal of free electrons is a determining factor in the minimum operating range and minimum target size. Clean-up of the water vapor is therefore, an important phenomena to be considered.

Accordingly, it is -an object `of this invention to provide in a gaseous discharge switching device means for replenishing the Water vapor to increase operational life. It is a further object to provide means for replenishing the water vapor which will be operative at the point of installation of the gaseous discharge switching device.

In accordance with the teachings of my invention, I provide means for retaining a predetermined quantity of silicic acid in powder form within the envelope of a gaseous discharge switching device, or, if desired, said retaining means may be externally mounted and communicate with ythe envelope of the device. The silicic acid powder retaining means is heated to la temperature sufficient to cause the silicic acid powder to decompose into water vapor and silica. The water vapor will diffuse throughout the gaseous medium.

An advantage of the present invention is the ease of operation, thereby permitting an extension of life without the necessity of extensive maintenance at the point of n installation.

Patented May 7, 1957 ice `Figure. 2 is a detailed vertical transverse section of a component of the invention;

Figure 3 is a detailed vertical transverse section of -a modification of the present invention; and

Figure 4 is an enlarged side elevlation of an: alternative embodiment. Y

Referring to Figure 1, the glass reservoir 1 of a transmit-receive gaseous discharge device is shown communieating with'the metal envelope 2. Positioned within and supported 'by this glass reservoir Iis an auxiliary electrode 3 with a dielectric sheathing 4. Electrode 3 may be provided with a top cap 5 for connection to a suitable voltage supply. At predetermined points, a portion of sheathing 4 may be removed to facilitate attachment of supporting rods 6 and 7, extending at right angles, to the core of electrode 3.

A sleeve 8, desirably of a refractory metal or ceramic, is affixed to rods 6 and 7 by conventional methods. One end of sleeve 8 may be crimped as shown at 9. The open end of sleeve 8 is packed with a perforate material 10. In the preferred embodiment, I have found quartz wool to be desirable.

A coil of an insulated heater Wire 11 surrounds sleeve 8 as shown. One end of-said heater coil is connected to supporting rod 7, as at 12, while the other end is connected t-o a tab 13 which may be sealed through glass .envelope 1. A top cap 14 may be provided -as a lead for a voltage supply shown at 15.

In detail as shown in Figure 2, sleeve 8 is closed at one end las at 9. A quantity of silicic acid powder 16 is contained Within said sleeve. A tight pack of quartz wool 10 is provided at the open end.

A modification of the present invention as shown in Figure 3, provides a perforated powder retaining sleeve 18, with top and bottom lsections 19 and 20. Supporting rods 21 and 22l are attached to sleeve 18, and may be aixed to the core 3 of `an electrode las shown in Figure 1. A tube 23 is positioned yaxially within sleeve 18 and may be supported by the top and bottom sections. A coil of insulated heater wire 24 extends within tube 23 and is connected to supporting rod 22 and an external connection, substantially as shown in Figure 1. The silicic `acid powder is retained with sleeve 18 as shown at 16.

In Figure 4, I have shown an alternative embodiment of the present invention which may be employed in devices without :an auxiliary electrode or antitransmit-receive devices, commonly found in radar systems to disconnect the ultra high frequency generatorv from the antenna when a returning signal is received.

In this embodiment, metal envelope 25 may be provided with a glass envelope 26 communicating with the gaseous atmosphere enclosed by the metal envelope. A supporting Irod 27 with two members 28 and 29 extending at right angles thereto, support sleeve 30 in a manner substantially similar to that shown in Figure 1.

By heating the powder retaining sleeve to a temperature of approximately 1000 C. with a suitable voltage supply, the silicic acid powder will decompose into water vapor and silica. The w-ater vapor diifuses into the gaseous atmosphere through the quartz wool shown in Figures 1 and 2, or the perforated sides in Figure 3.

In the practice of this invention, a quantity of five milligrams of silicic acid powder heated to approximately 1000n C. for three minutes gave a yield of approximately 56 hundredths of a milligram of water vapor.

While I have shown and described several embodiments of this invention, its teachings m-ay be practiced in various modifications of gaseous discharge switching devices em ploying water vapor, such as pre-transmitteceive, antitransmit-receive, and band pass transmit-receive devices.

What I claim and desire to secure by Letters Patent is:

l. A gaseous discharge switching device comprising a hermetically sealed enclosure, an ionizable atmosphere vs'ithii'lA 'si'd'enclo'sum an eiefti'Odmei'`t`ii `ii aftll/"Witii: in said enclosure, a plurality off spaced transverse support members mounted at an intermediateA point onxsaid electredes :a container sul'jprtelfby"saidV transyers inentbers parallel with said electrode, a 'qunttyolf silicic acid powder 4within said cortainer,`"a hetercil encircling said container with a legv thereof electricallycnnected to ya transverse surfport member and the? opposite leg Vextending outside said enclosure for external circuit'connection, said heater coiYWheIi energized adapted to heat said powder' to a temperatureapgiximately 1000 C'. to thereby introduce water Vapor into saidatrhosphere.

2. A" gaseous discharge switching," dvtf Comprising al hermetrically sealed `enclosureiriludiig ametallic 'en -f velopefand ai, dielectric hulbfrnembefrenternallymounted thereon, 'an ion'iiable attireJll-lr'e4 saidenclosure,Y a wirefcondu'ctor extendingfaxially within', bulb* Inerti-r ber, a pair-of'spaced transverse support nrenlbers'mlounted at yan intermediate point on said conductor, a hollow rnemberof a high ternpcraturersistant material mounted parallel with vsaid conductor and supported said bulb member by said transyerse members, a heater coil t 4 l surrounding said hollow member with a leg thereof electrillyinctdtca transverse support `ren`iber and the opposite leg extending 'through said bulb member for external circuit connection and a quantity of silicio acid powder contained within said hollow member adapted to introduce water vapor into said atmosphere when said coil heats said container to aitemperature of approximately'l' C.

References YCited the tile of patent UisuTnDY STAT-Es PATENTS 411,019 Edison Sept. 17, 1889 1,172,568 Schroter Feb. 22, 1916 2,082,268 Varian June 1, 1937 2,454,761 Barrow et al Nov. 30, 1948 2,496,865 Fiske Feb. 7, 1950 2,605,438 Stutsmian July 29, 1952 y FOREIGN PATENTS 8,927 Great Britain n June 8, 1916 230,467 Great Britain Iune 4, 1926 590,206 Great Britain July 10, 1947 matr; wn.. 

